Severe hypercarbia resulting from inspiratory valve malfunction in two anesthetized horses
Baxter, G.M.; Adams, J.E.; Johnson, J.J.
Journal of the American Veterinary Medical Association 198(1): 123-125
1991
ISSN/ISBN: 0003-1488 PMID: 1995568 Document Number: 375664
Severe hypercarbia was documented by arterial blood gas analysis in 2 adult horses anesthetized for exploratory laparotomy. Both horses appeared to be adequately anesthetized, but continued to breathe against the ventilator. In both cases, the inspiratory valve on the anesthesia machine was found to be stuck open, permitting expired CO2 to return to the inspiratory limb of the anesthetic circuit and to be inhaled with the next breath. Correction of the malfunctioning valve alleviated the hypercarbia. Problems with the flow valves of the anesthesia machine should be suspected when anesthetized horses breathe against the ventilator and develop severe hypercarbia.